Overview
ISO/TS 18827:2017 - Nanotechnologies - Electron spin resonance (ESR) as a method for measuring reactive oxygen species (ROS) generated by metal oxide nanomaterials - specifies a standardized, spin-trapping ESR procedure to detect and quantify ROS produced by metal oxide nanomaterials in aqueous, cell-free conditions. The technical specification targets detection of the biologically relevant ROS: hydroxyl radical (•OH), superoxide anion (O2•–) and singlet oxygen (1O2) using species-specific spin traps and excludes ESR methods that do not use spin trapping agents.
Key topics and requirements
- Purpose: Provide a reproducible ESR-based method to assess ROS generation potential of metal oxide nanomaterials as part of nanotoxicity evaluation and physico‑chemical characterisation.
- Target ROS and spin traps:
- DMPO for hydroxyl radical (DMPO/•OH adduct)
- BMPO for superoxide (BMPO/OOH adduct)
- TPC for singlet oxygen (TPC/1O2 adduct)
- Positive controls and validation: describes use of established radical-generating systems (e.g., Fenton reaction, hypoxanthine–xanthine oxidase, rose bengal photosensitization) and zero-baseline controls to demonstrate assay suitability.
- Procedure elements: preparation of nanomaterial suspensions, reagents and spin trap stock solutions, reaction conditions, sample injection and ESR measurement of spin adduct spectra, and calculation/standardization steps.
- Interferences and limitations: addresses sampling, timing, potential assay interferences, and the importance of controlling physico-chemical parameters (pH, light, aggregation) that influence ROS formation.
- Output: ESR spectra (spin adduct fingerprints) enabling detection and semi-quantitative assessment of ROS generation.
Applications and who should use it
- Researchers and laboratories characterising metal oxide nanomaterials (e.g., TiO2, ZnO) for oxidative potential.
- Nanotoxicologists and risk assessors evaluating ROS-mediated cytotoxicity and mechanistic hazard data.
- Product developers in biomedical devices, cosmetics, coatings, pigments, and environmental nanomaterials seeking early-stage screening of oxidative reactivity.
- Quality control and regulatory testing labs requiring standardized ESR spin‑trapping methods to support safety dossiers and comparability studies.
Practical value: ISO/TS 18827:2017 provides a reproducible, cell‑free screen to predict oxidative stress potential, support hazard identification, and inform further in vitro or in vivo testing strategies.
Related standards
- ISO/TS 80004‑1:2015 (nanotechnology vocabulary) - terminology referenced in the specification.
- ISO/TS 10993‑5:2009 and ISO/TS 10993‑12:2012 - referenced for test sample and control definitions used in biological testing contexts.
Keywords: ISO/TS 18827:2017, ESR, spin trapping, ROS, nanotechnologies, metal oxide nanomaterials, DMPO, BMPO, TPC, nanotoxicity, reactive oxygen species.